CARDIOVASCULAR REVASCULARIZATION MEDICINE

Mobilization of human CD34+CD133+ and CD34+CD133%u2212 stem cells in vivo by consumption of an extract from Aphanizomenon flos-aquae-related to modulation of CXCR4 expression by an L-selectin ligand?

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Gitte S. Jensen, Aaron N. Hartb, Lue A.M. Zaske, Christian Drapeau, Niraj Guptad, David J. Schaeffere and J. Alex Cruickshank

e. Department of Veterinary Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, USA

The coauthor C. Drapeau is Chief Science Officer for StemTech Health Sciences, which distributes the product StemEnhance, used for the in vivo part of this paper. No other authors have any commercial interest in the subject matter. Available online 29 August 2007.

Abstract
Objective
The goal of this study was to evaluate effects on human stem cells in vitro and in vivo of an extract from the edible cyanobacterium Aphanizomenon flos-aquae (AFA) enriched for a novel ligand for human CD62L (L-selectin).

Experimental approach
Ligands for CD62L provide a mechanism for stem cell mobilization in conjunction with down-regulation of the CXCR4 chemokine receptor for stromal derived factor 1. Affinity immunoprecipitation was used to identify a novel ligand for CD62L from a water extract from AFA. The effects of AFA water extract on CD62L binding and CXCR4 expression was tested in vitro using human bone marrow CD34+ cells and the two progenitor cell lines, KG1a and K562. A double-blind randomized crossover study involving 12 healthy subjects evaluated the effects of consumption on stem cell mobilization in vivo.

Results
An AFA extract rich in the CD62L ligand reduced the fucoidan-mediated externalization of the CXCR4 chemokine receptor on bone marrow CD34+ cells by 30% and the CD62L+ CD34+ cell line KG1A by 50% but did not alter the CXCR4 expression levels on the CD34 cell line K562. A transient, 18% increase in numbers of circulating CD34+ stem cells maximized 1 hour after consumption (P<.0003). When 3 noncompliant volunteers were removed from analysis, the increase in CD34+ cells was 25% (P<.0001).

Conclusion
AFA water extract contains a novel ligand for CD62L. It modulates CXCR4 expression on CD34+ bone marrow cells in vitro and triggers the mobilization of CD34+ CD133+ and CD34+ CD133 cells in vivo.